869809 has 2 divisors, whose sum is σ = 869810. Its totient is φ = 869808.

The previous prime is 869807. The next prime is 869819. The reversal of 869809 is 908968.

It is a happy number.

869809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 846400 + 23409 = 920^2 + 153^2 .

It is a cyclic number.

It is not a de Polignac number, because 869809 - 2¹ = 869807 is a prime.

Together with 869807, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (869807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 434904 + 434905.

It is an arithmetic number, because the mean of its divisors is an integer number (434905).

2⁸⁶⁹⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

869809 is a deficient number, since it is larger than the sum of its proper divisors (1).

869809 is an equidigital number, since it uses as much as digits as its factorization.

869809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 869809 is about 932.6355129417. The cubic root of 869809 is about 95.4570405175.

The spelling of 869809 in words is "eight hundred sixty-nine thousand, eight hundred nine".